\begin{tikzpicture}
    \tkzDefPoints{0/0/B,  4/0/C, 0/2.5/A, 4/2.5/D}
    \tkzDefLine[mediator](A,C)  \tkzGetPoints{e}{f}
    \tkzInterLL(A,D)(e,f)   \tkzGetPoint{E}
    \tkzInterLL(B,C)(e,f)   \tkzGetPoint{F}
    \tkzInterLL(A,C)(e,f)   \tkzGetPoint{O}
    \tkzDrawPolygon(A,B,C,D)
    \tkzDrawSegments(A,C  E,F  A,F  C,E)
    \tkzMarkRightAngle(E,O,A)
    \extkzLabelAngel[0.5](C,A,D){$1$}
    \extkzLabelAngel[0.5](A,C,B){$2$}
    \tkzLabelPoints[left](A,B)
    \tkzLabelPoints[right](C,D)
    \tkzLabelPoints[right=.5em](O)
    \tkzLabelPoints[above](E)
    \tkzLabelPoints[below](F)
\end{tikzpicture}

